CHOKU! Manga

Manga Summary:
Serika, a blunt and socially inept high school girl, has never had a friend before. However, she does have a boyfriend or at least she thinks she does. So what does she do? She takes a dump in the bathroom her boyfriend Nao plays games in and sprays him with blood. Why? Because that's what lovers do. The hilarity ensues as she learns the meaning of friendship and human interaction.